In conventional electrolyte-supported solid oxide fuel cell stacks (hereinafter, referred to as “SOFCs”) and electrode-supported SOFCs, sintering at a high temperature (e.g., 1400° C.) is performed in order to obtain a dense and highly-gastight electrolyte layer. In recent years, metal-supported SOFCs in which a fuel electrode, an air electrode, and an electrolyte layer are supported over a metal plate have been developed in order to reduce the thickness and to improve the robustness.
Patent Document 1 discloses a metal-supported SOFC in which a fuel electrode, an electrolyte layer, and an air electrode in the shape of thin films are layered in this order on a porous metal substrate. In the production process of this SOFC, after an electrolyte material is applied to and dried on a fuel electrode, pressing treatment is performed. Subsequently, sintering is performed to form a dense electrolyte layer.